A walking truck including a platform pivotably supported above a base frame, inner racks and outer racks bilaterally disposed below the base frame and coupled by transmission shafts and cranks, a first motor drive controlled to move the inner racks and the outer racks alternatively for going upstairs or downstairs, a second motor drive controlled by a pendulum and two micro switches to move a balance linkage in either direction for keeping the platform in balance as the walking truck goes upstairs or downstairs.